Radar level gauges (RLGs) are suitably used for making measurements of the level of products such as process fluids, granular compounds and other materials contained in a tank. An example of such a radar level gauge can include a transceiver for transmitting and receiving microwaves, a signal propagating device arranged to direct microwaves towards the surface and to return microwaves reflected by the surface to the transceiver, and processing circuitry adapted to determine the filling level based on a relation between microwaves transmitted and received by the transceiver.
The signal propagating device may be a directional antenna, adapted to emit free propagating electromagnetic waves into the tank and receive a reflection of those waves. Such an RLG is sometimes referred to as a non-contact RLG. The antenna may be adapted to a specific frequency band, and the currently most used frequency bands have center frequencies of 6 GHz and 24 GHz. Obviously, antennas adapted for such widely separated frequency bands will be structurally different, and require different wave guide matching.
Alternatively, the signal propagating device may be a probe extending into the product in the tank. The emitted signals are guided by the probe, and the RLG is often referred to as a guided wave radar (GWR) level gauge. There are several different types of probes, each adapted for specific center frequencies and with different structural features.
The radar level gauge will have to be adapted to the type and design of signal propagating device. More specifically, the tank feed though structure, which is securely fitted to the tank flange, and acts as an interface between the tank and the radar level gauge, will need to be specifically adapted to the signal propagating device. Of course, the tank feed through structure will also need to be specifically adapted to the size and type of the tank flange. This leads to a great number of individual parts that need to be manufactured and stored by suppliers of radar level gauges. This, in turn, leads to inefficient logistics and manufacturing economy.